I live in Hawaii and have a 6 yo QH/Arabian mare that foaled 10/25/2002. About 5 or 6 days after foaling (no complications) hair started coming out of her mane & tail by the hands' full. Her coat never looked better, and she is in good spirits and seems healthy in every other way.

I called the vet and he said it could be hormonal or selenium toxicity. She is an 850 - 900 lb. mare and I'm feeding daily: 20lb. alfalfa cubes (no baled hay in Hawaii), 2 lbs. sweet feed, and 1 lb. calf manna. The vet said that if selenium were a problem, it would be coming from the calf manna, so I cut that out.

Now today I think I see evidence of hoof delamination. There is a definite gap between the hoof wall and the sole of her right front foot. One of her rear feet seems to be chipping up the hoof wall as well. She shows no sign of lameness although this mare has been mysteriously and intermittently lame ever since we bought her. There is no indication that she ever foundered.

The farrier is coming out to take a look. Does anyone have an explanation for all this? BTW, there are approx. 60 horses on this farm and none of the others show similar symptoms -- seeming to make the idea of selenium toxicity unlikely.

Aloha Jeff, I'm in Hawaii also. This is a long shot, but could it possibly be haole koa?? You know, the weedy tree with yellow flowers and brown seed pods. A long shot because the other horses aren't losing hair but horses are said to become immune after their first koa eating hair loss. A few years ago our horses totally lost their mane and tails (not attractive) by chewing on the bark of the tree. We thought they were ok because the leaves & flowers were high across a fence, but who knew they also chewed on the bark. I'm sure your local vet knows about the koa, but could there possibly be trees mare's getting to that you may not be aware of. As for the hoofs, I wonder if it's just a coincidence. Have you changed her diet she she gave birth? I don't know if this koa theory is helpful, but just a possibility. I also have a little arab mare with a beautiful mane and tail (which took three years to grow out after the koa bark episode!)

Hello Jeff and Linda, Though hormonal alopecia do occur in humans, they are not well established as a cause of hair loss in horses. The lack of other symptoms argues against Selenium toxicity. Personally I do not think the Calf Manna is as likely as the alfalfa: alfalfa is a selenium concentrator. If grown on selenium rich soils it can occur is high level in the plant. CM is selenium supplemented but the level they shoot for is fairly low (SELENIUM...(Min) 0.1 ppm) but accidents happen.

I have to plead ignorance about haole koa and I cannot find anything in any of the literature I have Linda. Do you know why this plant causes hair loss?

Jeff I would take a three prong attack: 1) Have the skin checked carefully for signs of inflamatory disease. 2) Have all the feed stuffs checked for excessive Selenium. 3) Consider the food stuffs may be old so vitamin deficient. DrO

Aloha Dr. O, the local legend is that the koa is very very high in protein. That's the most scientific explanation I've heard. It does not have an affect on cattle or goats. Horses can eat a little with no hair loss, but it is very equine delicious. If they can get to it, they will eat a big amount and quickly lose mane and tail. It's also said that after the first hair loss episode, they will be immune and can eat koa for life with no consequences. I did read article on this Forum about Hair Loss and there was a brief mention of a toxic plant living in Hawaii and Guam. I have wondered if this plant grows anywhere on the mainland. It's very pervasive here.

Jeff, I don't think Calf Manna has selenium as an ingredient because while horses need it in very low amounts, I don't it is recommended for cows or sheep and in fact is I think toxic to sheep and Calf Manna is safe for all livestock.

I say this because I went to a feed seminar not long ago and the feed company representative pointed this out as a reason to feed their horse supplement. I do know that if you are feeding several different horse vitamin and minerial supplements you need to check the level of selenium totals to be sure you don't overdose on it. In this case less selenium is better than an overdose which can become toxic.

I have never heard of the koa plant since I live in Kansas. I would be tempted to have a blood test run and also a hair analysis to see just what is killing the hair root causing the hair loss.

I did some research on the koa. it's name is leucaena leucocephala and here is quote on toxity: "Toxicity. The leaves and seeds contain the glucoside mimosine, which may cause loss of hair in horses and young cattle. The addition of iron salts decreases toxicity, and if the treated material is allowed to stand for a week before being mixed with feeds, little toxicity remains. The mimosine content can also be reduced by soaking in water and drying. Sheep should be introduced to koa haole gradually to increase their ability to detoxify the feed. The ill effects of mimosine are erratic, and sometimes no effects are observed even when koa haole is the sole feed. The young foliage is very palatable to cattle, rich in protein and nutritious. "

Thank you all for your help. I've found that there is in fact a lot of haole koa on the ranch. I've never observed her eating it, but it is certainly possible. It just seems awfully coincidental that this would occur immediately after foaling.

The vet is coming out to do the check for inflammatory disease but the haole koa diagnosis seems the best fit at the moment. My wife is sick at the thought of waiting 2 or 3 years for her mane and tail to grow back :-)

Hi, I'm in Hawaii also... no haole koa near our horses... but my mare whose foal was weaned off several months ago is losing a lot of hair, also. Primarily alfalfa diet, with supplements. What is considered a toxic intake of selenium, and how much is generally supplied in the alfalfa (hay and cubes)? Mahalo! ~Clare

Welcome to horseadvice.com Clare, You will find the answer to most of your questions at » Care for Horses » Nutrition » Selenium in Horses. The amount of selenium present in forages varies and the factors that effect the amount are explained in the article. If the soil is very rich in Selenium alfalfa will concentrate it. DrO

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